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Sharp Noise When Reversing Is Caused By The Straight-Toothed Gear Design, Unlike That Used In Normal Gears, Which Are Quieter And Smoother
When engaging the reverse gear and accelerating the vehicle, a sharp and characteristic noise can be heard. This noise, common in various cars, does not indicate a mechanical defect, but is explained by the type of gear used in the cars’ reversal system.
The majority of forward gears use gears with helical teeth, which ensure progressive and smooth contact between components, significantly reducing noise and wear over time. In contrast, the reverse gear adopts straight-toothed gears, whose contact occurs simultaneously and directly.
This difference in the shape of the mechanical parts is the main reason for the noise. The abrupt contact between the straight teeth generates more vibration and, consequently, more noise, as well as greater wear over continuous use.
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Automotive mechanics specialist Daniel Monteiro explains that the sound of the reverse gear is a natural consequence of this design. He emphasizes that, despite the auditory discomfort, it is a completely expected effect and poses no risk to the vehicle.
According to a report published by CNN Brasil, the use of this type of gear is common because it is cheaper and more efficient in quick maneuvers, where sound comfort is not a priority.
